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/* $Id$ */
/*
libg3d - 3D object loading library
Copyright (C) 2005-2009 Markus Dahms <mad@automagically.de>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <math.h>
#include <g3d/types.h>
EAPI
gboolean g3d_vector_normal(G3DVector ax, G3DVector ay, G3DVector az,
G3DVector bx, G3DVector by, G3DVector bz,
G3DVector *nx, G3DVector *ny, G3DVector *nz)
{
*nx = ay * bz - az * by;
*ny = az * bx - ax * bz;
*nz = ax * by - ay * bx;
return TRUE;
}
EAPI
gboolean g3d_vector_unify(G3DVector *nx, G3DVector *ny, G3DVector *nz)
{
G3DFloat r;
r = sqrt(*nx * *nx + *ny * *ny + *nz * *nz);
if(r == 0.0F)
*nx = *ny = *nz = 0.0F;
else {
*nx /= r;
*ny /= r;
*nz /= r;
}
return TRUE;
}
EAPI
gboolean g3d_vector_transform(G3DVector *x, G3DVector *y, G3DVector *z,
G3DMatrix *matrix)
{
G3DVector vector[4], result[4];
guint32 i, k;
vector[0] = *x;
vector[1] = *y;
vector[2] = *z;
vector[3] = 1.0;
for(i = 0; i < 4; i ++) {
result[i] = 0.0;
for(k = 0; k < 4; k ++)
#if 0
result[i] += matrix[i * 4 + k] * vector[k];
#else
result[i] += matrix[k * 4 + i] * vector[k];
#endif
}
*x = result[0];
*y = result[1];
*z = result[2];
return TRUE;
}
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